1. Field of the Invention
The invention relates generally to personal flotation devices and particularly to a personal flotation device incorporating a ballast member.
2. Description of the Prior Art
Heretofore, accidental immersion often resulted in death by two causes, aspiration leading to asphyxiation or hypothermia. A life saving system, to be viable for more than a few minutes, must successfully address both of these issues. Current life vests supply the requisite amount of buoyancy to return the victim to the surface, but often require a conscious victim""s involvement to keep the airway clear. While it is common practice, as well as legally mandated, that all civilian, commercial, and non-civilian vessels carry Coast Guard approved life vests, many current water safety products provide only a limited portion of the safety they are capable of providing. They do provide for positive buoyancy during the shock of the initial entry into the water, but by incorporation of the concepts disclosed herein are capable of providing significantly improved airway protection after the initial insult with significantly increased reliability of airway protection and less bulk, cost and, consequently, more compliance.
By force of habit, life vests are currently designed after clothing and as such they open in the middle of the chest, producing a point of reduced buoyancy where it is least acceptable. The division of the forward chamber into two halves produces two side chambers which are each capable of generating righting moments in the water. When a righting moment is created on the body of an exhausted or unconscious individual, they can be stabilized in a face down or side down position. If the left or right side is out of the water, concurrent loss of muscle tone in the neck allows the face, nose, and mouth to be positioned underwater. Thus, current constructions of many life vest are really only adequate for conscious, alert, and active victims because they require participation, constant monitoring and adjustment by the user to keep the face and airway out of the water.
On sudden entry into the water, water on face actuates the Dive Reflex, which is a rapid uncontrollable inhalation. This reflex often results in aspirating water with its consequent choking and coughing. This distress further complicates the victim""s ability to right themselves and assist in their own rescue. It is often the case that the sailor who is knocked overboard by the boom of the sail or is swept overboard by a wave, can suffer a temporary loss of consciousness. During this initial interval it is important that their life vest not only buoy them to the surface, but that it also obtain and maintain the victim""s face and airway out of the water until consciousness is regained.
The only life vest that is of any value is the life vest that is worn. Compliance can not be ignored as an important criteria in the design and manufacture of any safety product. The actual use of safety vests has begun to move forward by the hybrid personal flotation devices. The HPFD is a combination of a certain amount of inherently buoyant material along with an additional amount of inflatable buoyancy. Because of the reduced amount of bulk and therefore increased convenience associated with the hpfd, their acceptance is growing. U.S. Pat. No. 4,681,552 issued Jul. 21, 1987 to William Courtney, addresses the value of hybrid personal flotation devices. Like many vest style safety products and in particular all buoyancy compensators, the BC vest described in U.S. Pat. No. 4,681,552, when both chambers are inflated in the configuration disclosed in FIG. 1, would stabilize the user on their side, placing their airway underwater if the user was unable to hold their head up.
The vest that is constructed entirely from inflatable chambers is much more comfortable, convenient and therefore is frequently worn by itself and is now approved by the United States Coast Guard. The purely inflatable product such as the inflatable sailing harness, wind breaker, safety device, because of its compactness, is often the actual product worn by the victim. Many purely inflatable safety products attempt to compensate for the lack of inherent buoyancy by generating large amounts of lift. The use of excessive lift often results in the use of air under the arms where it creates the side up righting moment that can jeopardize the airway, a design defect addressed by the instant invention.
The airlines, because of their insoluble stowage problems are allowed the use of a purely inflatable device that has redundant chambers to guard against the failure problems inherent in single chamber safety devices. The scuba diver also wears a purely inflatable device known as a buoyancy compensator or xe2x80x9cBC,xe2x80x9d which looks like a traditional life vest but because it lacks at least reliability is not called such. The sailor is known to use inflatable wind breakers. All these devices, as well as many not described here, that are meant to provide surface flotation to individuals in the water, would be markedly improved by incorporation of the concepts described herein. Whether constructed solely from inherently buoyant means as are traditional life vests, or constructed from a hybrid composition of inherently buoyant and partially inflatable, or constructed from purely inflatable components, the specific location of a minimal amount of ballast in accordance with the construction herein disclosed would confer dramatic improvements in bulk, cost and compliance and consequently, in safety and survival statistics at sea.
The prior art on the use of dual chambered safety vests includes Swedish patent #203592 issued to Lindqvist on April 1966. This patent discloses a dual chambered product with a large forward chamber which would allow the victim to be stabilized in either a heads up position or if unconscious the victim could be stabilized lying over the forward float with their nose and mouth underwater. The device also relies on the victim""s legs to apply tension to a draw string to pull the rear chamber up behind the victim""s neck. For the active participant the product may have some utility but would be unsuccessful if not closely regulated. In addition the product is needlessly large and thus unnecessarily bulky when deflated, a feature that often results in the product being stored in a locker rather than being worn.
The buoyancy compensator is a convenience product that has unfortunately replaced the diver""s safety vest. The buoyancy compensator is a specific adaptation of a purely inflatable safety product that is worn by the diver for use both at the surface and underwater. The product evolved from the orally inflated safety vest that had the appearance of and was often called a horse collar vest. After decades of diving it was decided that the diver would benefit from the inclusion of a chamber to hold air while under water to offset the loss of buoyancy that occurs as the diver""s thermal protective gear is compressed at depth. The initial compensators for this shift in buoyancy were containers that could be filled with air to displace water and therefore generate increased buoyancy as the diver""s wet suit was compressed by the water. In an emergency this device could be easily disconnected from the diver.
The next step in the evolution of the buoyancy compensator was to use the air cylinder to inflate the safety vest, a product designed to protect the airway at the surface. Its proximity to the face and neck, its obstruction of the chest and therefore the site of controls for the dry suit diver, its general bulk and appearance left room for the advent of the life vest style buoyancy compensator. The initial detached, canister buoyancy compensators were of low volume and easy to ditch. The horse collar and then the life vest style buoyancy compensator became voluminous. The larger lift capacity became equivalent to the better the product. Buoyancy compensators are available with 80 lb. lift capacities. At the surface the high lift product conferred a sense of security because it would buoy the diver far above the water as long as diver remained in firm control of the product. As the diving population became more diverse in health and age, the false sense of security led to marked competitiveness over the amount of lift that could be attached to the diver. The product is so confused with security that a diver can not get onto a dive boat without wearing a high lift buoyancy compensator for xe2x80x9csafetyxe2x80x9d reasons.
The inflatable products worn by scuba divers as disclosed in Greenwood""s U.S. Pat. No. 3,436,777; Robert""s U.S. Pat. No. 3,747,140; Walters"" U.S. Pat. No. 4,016,616; Wright III""s U.S. Pat. No. 4,137,585; Scott""s U.S. Pat. No. 4,176,418; Maness""s U.S. Pat. No. 4,324,234; or Courtney""s U.S. Pat. No. 4,645,465 and 4,681,552, and all buoyancy compensators in the prior art are complicated by the attachment of an air cylinder that undergoes shifts in buoyancy throughout each dive as the cylinder empties and becomes more buoyant. The size of the shift in buoyancy is directly proportional to the size of the cylinder used. The nature of the shift in buoyancy, whether the cylinder ends up positively buoyant or only less negative, is a combination of cylinder composition, most commonly aluminum or steel and the water density, fresh, brackish or salt. Some air cylinders become six pounds positively buoyant when empty in sea water. This cylinder will float on its longitudinal axis as will the diver who is attached to that cylinder. Consequently, if for any reason the diver is unconscious, such as from a minor embolism from rapid ascent, blackout, trauma, medical problem or just over exhausted after being stranded at sea, they will eventually lie along side the air cylinder with their airway under the water and statistically the deaths are recorded as drowning. The current management of the life threatening side righting moments of every vest style buoyancy compensator is to disclaim liability for keeping the airway out of the water.
The instant invention discloses the integration of a very small amount of non-releasable weight exactly opposite the diver that converts the only inflatable worn by divers into a product that will protect the airway if the diver is unable to. The attachment of weight to the air cylinder in the prior art has been a way for carrying the ballast necessary for the diver to be able to submerge, and thus were designed to carry significant amounts of weight. Patents issued have turned on the design of the release system. The dive community demands that the attachment of significant amounts of weight must be able to be quickly released by one hand, by either hand. The release mechanism must be sure in that it must not accidentally release, but once the diver chooses to release the ballast the mechanism must be simple enough that it will not fail. All of the prior art by way of its incorporation of reliable release mechanism assures the diver that as an emergency is evolving and their weights are dropped to gain a better surface attitude, the air cylinder that was critical for use under water and is now empty will be attempting to float the diver on their side. If the diver is unable to oppose this action, their nose and mouth will be forcefully submerged.
It is to be noted that in U.S. Pat. No. 4,455,718, the quick release means is positioned centrally to allow access by either hand in the event of an emergency release. Prior to the release, the central positioning of the quick release mechanism necessitates that the weights as demonstrated in FIGS. 1 and 2 and be placed off center, potentially reenforcing the side righting moments of the life vest style buoyancy compensator. The keel retaining system disclosed is built into the buoyancy compensator so it will not be lost or left at home, the buoyancy compensator cannot be safely used without this critical component. In patent U.S. Pat. No. 3,670,509 it is noted that the ballast is located in front of the tank, close to the back of the diver and consequently closer to the axis of rotation which parallels the spine of the diver, thereby drastically reducing the rotational energy generated per unit of keel weight. This greatly reduces the effective strength of the angular rotation generated by a particular amount of ballast. Since some divers in the tropics may dive with only a few pounds of weight, it is important that the keel weight be kept as far away from the axis of rotation as is possible to maximize the strength of the righting moment. The critical location is on the exact opposite side of the tank from the diver. U.S. Pat. No. 3,670,509 refers to xe2x80x9csubstantial reducingxe2x80x9d the tendency to force the diver face into the water. Use of the disclosed improvements will not allow the face to remain underwater. The ballast in patent U.S. Pat. No. 3,670,509 that attempts to reduce the face down righting moment, positions the diver so that they are able to xe2x80x9c. . . activate the weight release mechanism.xe2x80x9d, with the loss of the ballast the diver then would be back to floating on their side with their airway underwater. U.S. Pat. No. 3,967,459 locates the weight system inferior and adjacent to the diver nearly the exact opposite as disclosed herein. It is also noted that this weight system is intended to be released in an emergency reestablishing the tendency of the cylinder to submerge the diver""s airway. The integrated ballast system of U.S. Pat. No. 4,752,263 is similar in that it is releasable, and located inferior and adjacent to the diver allowing for an airway endangering surface position. The ballast system disclosed in U.S. Pat. No. 2,120,420 places weight symmetrically about the diver which would totally eliminate any heads up righting moment and in fact would stabilize the diver 50% of the time in a face down position, additionally, this system is not designed to be used with an air cylinder, but rather a surface supply air system.
The instant invention achieves many critical features including providing that the weight be permanently attached, so that in an emergency it cannot be dropped. Since the keel weight must be small enough to not compromise surface safety, it must be located on the cylinder exactly opposite the diver where it generates the maximal rotational energy per pound of keel, rotational energy desperately needed to repeatedly turn the unconscious diver over onto their back against minor righting moments caused by limbs, variations in body density, and attached gear. In particular, if the victim dives near heavy surf where the waves can flip a victim over onto their face, a strong heads up righting moment is essential.
Another critical problem with the use of all current buoyancy compensators is that they combine high lift surface flotation needs with low lift underwater buoyancy needs. That same device at depth entraps pressurized air by design. The 190 lb. diver at 120 feet underwater requires nine pounds of air in their buoyancy compensator due to compression of their cold water wet suit, should that diver begin an uncontrolled ascent because; their regulator malfunctions, their tank is empty, they lose their mask and become disoriented, the power inflator sticks on their buoyancy compensators, they suffer a minor medical problems as they attempt an emergency assent, for whatever the reason, as the diver ascends, the air in their buoyancy compensator begins to expand. Ten pounds of air at 99 feet underwater, increases to 13.3 pounds at 66 feet and increases to twenty pounds at 33 feet and doubles forty pounds during the last 33 feet of the water column, enough air to create excessively fast ascent rates.
Recommended safe ascent rates are in the process of being reduced from 60 feet per minute to 20-30 feet per minute. A buoyancy compensator that can contain 30 lbs. of air can accelerate a diver who is stationary less than 10 feet underwater to the surface at average velocities over the last 4 feet, in excess of 200 to 250 feet per minute. Ascent rates from greater depths or ascent rates with larger buoyancy compensators such as currently available products generating 40, 60 or 80 lbs. of lift are unknown. It is known that if a person""s lungs are fully inflated and they hold their breath while ascending three and a half (3xc2xd) or four (4) feet, their lungs will rupture. Pulmonary barotrauma introduces air into the circulation where it can obstruct circulation and result in infarction of the tissue involved. Since the diver is often vertical during an uncontrolled rapid ascent, the embolism most often travels to the brain. Unless the diver is re-compressed within minutes damage is permanent and possibly fatal. The prior art on buoyancy compensators, as is practiced in the diving community, unfortunately combines low lift buoyancy compensation needs with high lift surface flotation. The prior art buoyancy compensator is in desperate need of the many advances disclosed herein.
Once the conscious or unconscious individual is supported safely at the surface with their airway free and clear, the next major threat to the water borne victim whether recently returned from the depths or a survivor of a common carrier accident such as an airplane crash, is from; not being seen by search and rescue efforts, of being drowned while attempting a rescue or from hypothermia.
The rapid lowering of the body""s core temperature results in interruption of life sustaining cognitive activities such as staying in a tucked fetal position, which further aggravates heat loss. With the loss of cognition the victim stops monitoring and responding to changing surface conditions. Inevitably hypothermia interferes in brain stem activities such as musculoskeletal tone and respiration. It is widely known that hypothermia is the actual killer in most accidental immersions. In response to such knowledge, exposure suits have been developed to insulate individuals and preserve core temperature thus extending survival from minutes to hours. An effective exposure suit is a large, bulky item that is prohibitively expensive. Despite these serious drawbacks it is the only alternative to dying from hypothermia within minutes and as such it is a legally mandated safety device for the industrial sector where its costs, bulk and inconveniences can be borne. Exposure suit costs and bulk have prevented their use being required in the recreational, civilian or commercial carrier sectors such as airlines, liners, ferries etc. Therefore it is clear that despite recognition that hypothermia is the active process in death at sea, there has not existed until this time a viable, affordable, storable means to control hypothermia.
To address this deficiency in the prior art, the current invention addresses both aspects of safety at sea. Rescue can rarely be performed within minutes. Often the sailor on watch is not missed until the next watch, obviously the single handed sailor is never missed. The sinking of a civilian or commercial carrier is often unattended for many hours or longer. As is noted in Harrigan""s U.S. Pat. No. 2,114,301; Bennett""s U.S. Pat. No. 3,105,981; or DeSimone""s U.S. Pat. No. 4,187,570, there exists complex, bulky and costly means whereby jet pilots and navy personnel have personal power inflated life rafts. These automatically inflated life rafts require a cylinder whose cost alone is prohibitive to private and commercial carriers. The bulk of the cylinder, the bulk of the raft constructed from a fabric capable of withstanding pressurized inflation and high impact forces results in a device that is incompatible with civilian and commercial carriers such as airlines or ferries, yet alone individuals wind surfing, fishing from rubber rafts or touring ocean kayaks.
The present invention relates to water safety gear including life vests, integrated rescue products, and hypothermic protective gear, adapted for one-time use by the victim placed in the water by accident or for regular use by the water enthusiast whether a sailor or scuba diver.
The smallest safety vest that reliably protects the victim""s airway is ideal because of its lower cost, reduced bulk when deflated, and improved appearance, all factors that contribute to compliance with use, the true basis of success in any emergency. The current water safety vest distinguishes the two critical points of buoyancy, one behind the neck and head with the second point of buoyancy being in the area of the umbilicus, and one of ballast, behind the victim and their flotation chamber. A very small amount of buoyancy and ballast securely attached to the victim at these two points is sufficient to roll an individual over and put them on their back, thereby protecting their airway from submersion. Entry and adjustments are from below, from the side or if from the front then the front chamber must overlap and be maintained and secured in a central position. Only this combination of small buoyant chambers reliably creates safe positioning of the victim""s neck and head. This face up righting moment is generated regardless of the angle of entry into the water or level of conscious participation. This strong righting moment also compensates for the ongoing effects of rotational forces such as waves that at a certain point will overcome the lateral stabilization provided by the rear perimeter chamber.
Ideally the rear chamber is constructed to cradle the head and neck preventing it from drooping over backwards or sideways and becoming submerged. The chamber can be extended along the sides where they act much as outriggers, stabilizing the body from being rolled over because of wave action. The perimeter rear buoyant chamber defines a space, and actually forms a containment means for stowing a separating flotation chamber, such as a multi-function rescue safety product. It also is the ideal site of expansion that occurs when an inflatable life vest is actually inflated. All inflatable buoyant chambers upon inflation convert from a two dimensional product to a space occupying three dimensional object. This creates a shortening that results in constriction. Power inflated vests generally have an over pressure valve to protect against rupture but before this is actuated an unacceptable amount of pressure is applied to the thorax of the wearer. To compensate for this either the garment is very loose so that when it is inflated the wearer can still breathe or the chamber slides along a retaining strap or belt shifting the position of the inflatable bladder and thereby shifting the righting moment. Current inflatable vests upon inflation slide to the rear as an accommodation to the front entry. This pulls the buoyant means towards the back and results in greater moments of stability in the side high position which submerges the airway. In the current embodiment if the vest is entered from the front its closure is fixed. The rear buoyant chamber upon inflation stretches away from the center of the back and out towards the sides strengthening the lateral stability of the vest and the forward central buoyant bubble remains aligned along the center.
There are several reasons that most life jackets are vest style; the historical basis of clothing design, the need to locate the required amount of lift required by the regulatory agencies and the degree of fit. The buoyancy generated by the life vest must be able to be secured reliably about the torso of the wearer. Entry into the water or rough surface action must not strip the life jacket from the victim, in this regard the secure closure, appropriate sizing and an elastic component combine to provide a reasonable attachment. The only way to be assured that the victim and their life jacket will not be separated is by the inclusion of a crotch strap. Once again compliance is a function of comfort. If the crotch strap is loosely attached prior to entry into the water then easily adjustable while in the water, it might be used. A wet, limp, unconscious victim being tossed about by waves will require a retaining strap between the legs to optimize the survival value of any buoyant product attached to the victim. Its inclusion in a life saving system is necessary, the option of its timely use is a function of comfort and cosmetics. Another reason for the current vest design of water safety products is that the Coast Guard use to require certain amounts of buoyant lift for varying classes. Commercial requirements exceed those for personal use, but all classes displace such a large volume of water that the buoyant means needs to be spread out over a large surface area such as is provided by a vest style life jacket configuration, despite its serious drawbacks.
Some vest style life jackets have four righting moments; face up, back up, left side up and right side up. The current invention creates a broad base triangle. Central to this invention""s uniqueness is a small buoyant bubble that is centrally located in front of the wearer, and a small amount of ballast posterior. The front chamber is responsible for initiating the righting moment and the counterweight eliminates the side position, and supplies the rotational energy needed to roll the victim over onto their back thereby assuring that the victim""s face will be out of the water regardless of the angle of entry. Once the forward chamber has reached the surface, it in conjunction with the dynamics of a limp unconscious body, will oppose any tendency for the waves to roll the victim over into a face down position that would compromise the airway. If the front chamber is too wide, it can combine with the rear buoyant bladder and create a second, life threatening righting moment in which either side could be held at the surface and concomitantly the airway submerged. In summary, the rear buoyant chamber provides a base of support for the head and neck, supporting the airway and providing lateral stabilization, opposing rotational motion of the waves from over turning the victim into a face down position, but in the event that occurs, the forward buoyant bubble that is located at the umbilicus will automatically flip the victim back over onto their back, reestablishing the heads up orientation.
While the forward and rear buoyant chambers could be constructed form a single chamber, ideally two or more chambers confer several advantages. In this design one of the chambers is retained by a releasable system. This feature allows the wearer the option of being able to remove a chamber and use it as a distress marker, thus the preferred embodiment is to construct the forward chamber from a highly visible and radar reflective material. Separation also allows the chamber to be used as a rescue device. It can function as a rescue board to approach a swimmer in distress or used as a buoyant assist beneath the arms of the rescuer to provide lift in the event the rescuer is attempting to perform artificial respiration while in the water.
In adapting the product for the scuba diver, the separating chamber can be used under water by the advanced diver to mark a dive site such as in search and rescue attempts. The separating bladder can also be used as an underwater lift or salvage device rather than the common but unsafe practice of using the divers high lift buoyancy compensator as a salvage device. In the event that the object being salvaged slips from the divers grasp, the diver suddenly becomes markedly buoyant and is thrown into an uncontrolled ascent. In the event of a sudden increase in boat activity the diver could leave the separating chamber at the surface marking the dive site, so that boaters will avoid driving over the partially submerged diver. The universal retaining strap of the releasable chamber ideally has an elastic component to allow for distention of the bladder when it is inflated. The separating chamber when modified for use underwater in a buoyancy compensator must be reliably regulated. Safe and secure containment of the bladder underwater is critical. As helpful as additional buoyancy is at the surface, that same buoyancy underwater represents serious exposure to rapid ascent with its numerous serious problems. On the other hand the surface flotation chamber must also be simply and quickly deployed to be of assistance of an emergency at the surface.
Because the volume of the buoyancy compensator has been reduced to mitigate the chances of rapid ascent, it is foreseeable that the forward surface flotation chamber may not be deployed in an acute emergency underwater so the rear chamber and the disclosed keel weight have to be sufficient to protect the airway by establishing a heads up orientation with or without the deployment of the forward chamber.
When an air cylinder is attached to the heads up life vest, the life vests counterweight must increase in size to offset any additional outrigger effect. It is called a keel, because when the diver is lying face down at the surface and goes limp, the tank compensating keel weight, like the keel of the sail boat will roll the diver over onto their back, stabilizing the airway out of the water. The compensating portion of the name is because the size of the weight is in proportion to the type and size of the vest, cylinder and whether the water is fresh or salt. If the cylinder when empty is neutral to slightly negative it will sink allowing the diver to roll over onto their back. The keel weight in other words compensates for the buoyancy shifts of the diver""s jacket and air cylinder. If the cylinder remains negative when empty then the keel weight can be smaller but still must generate sufficient angular momentum to offset the secondary righting moments generated by an imbalanced weight belt and attached gear or bladders. If the keel weight is used as an adaptation to existing vest style buoyancy compensator, then it has to be strong enough to overcome the side righting movements generated by the common practice of using buoyancy under the arms.
Central to the tank compensating keel weight""s design is that it be made of a very dense material such as lead, and be located exactly opposite the diver on the back side of the tank. Traditionally the buckle that generates pressure on the belt that attaches the buoyancy compensator to the tank is located in the center at the back of the tank. Because the posterior central position is so critical for the performance of the keel, the buckle has to be moved off center. This shift in the cam buckles location results in a slight inconvenience in terms of reduced access but is necessary to preserve the critical location and therefore the righting moment of the compensating keel weight.
Ninety (90%) percent of drowned divers are often found with their weight belts still on and fifty (50%) percent of such are at the surface. Usually the weights are located along the waist and the amount runs from a couple of pounds to more than forty pounds. As the amount of weight increases, the keel weight needs to be located higher up the air cylinder to offset the placement of the weight belt. The dual tank band allows for a wide variation of weight placement. Obviously, the keel weight could be incorporated into the metal of the cylinder, adhered to the cylinder, enclosed in a covering of any sort, or even attached with magnetism. A pouch or cylinder could be used to contain lead shot or beach sand as long as it is located along the longitudinal axis of the cylinder and thereby serves to generate the heads up righting moment.
Additionally the concept of critical ballast is such that a certain amount of ballast is absolutely required in order for the diver to stay underwater. To facilitate the concept of safe diver weighting the tank compensating keel weight is also used to offset the inherent buoyant material from which the buoyancy compensator itself is constructed. Thus, because of the tank compensating keel weight, the buoyancy compensator, the tank, and regulator combination is neutral and as such does not contribute to the consolidation of additional ballast on the weight belt. If the quick release buckle of a consolidated weight belt should snag on a plant or slip out of hand during adjustment at depth the dangers of an uncontrolled buoyant ascent are somewhat mitigated because the shift in buoyancy is reduced by the amount of ballast used as a tank compensating keel weight.
While the forward chamber is not critical for protecting the airway of the scuba diver because of the effectiveness of the tank compensating keel weight, the forward chamber""s ability to provide additional high lift surface flotation fulfills an expectation in the sport. The key to the addition of high lift surface flotation to the diver underwater is its safe regulation. The operation of the forward chamber requires diametric opposed properties of the valve chosen to regulate the chamber. One embodiment employs the use of a variable fabric valve fabricated from a self releasable hook and loop fastener such as VELCRO(copyright) that can operate in three different modes, as a manual on/off valve, semi-automatic valve or a fully automatic valve. In addition, as the fabric valve ages its strength can be renewed by further increasing the interactive surface area.
The value of including a variable valve in line between the rear chamber and the forward chamber is that the diver can become more responsible with experience and training for the total amount of lift available to the diver underwater as well as at the surface and thus more responsible for uncontrolled ascent rates and consequently the risk of pulmonary barotrauma, arterial gas embolism and its frequent outcome cerebral infarction as well as the risks of decompression sickness.
Some dive instructors fear that the beginning student will not be able to perform an additional task in an emergency and therefore prefer that the entire buoyancy system automatically inflate choosing simplicity of operation at the expense of exposing the beginning diver to the consequences of a more rapid uncontrolled ascent, despite the fact that deaths have occurred during buoyant ascents while training in a swimming pool. In particular, since the student will be involved in a lot of surface drills and exercises, such as determining how much weight they require in order to be able to submerge, clearing their masks and snorkels, and since the first dives will be shallow, the consequences of rapid ascent are severe. As their experience grows and their comfort in the water with their gear and the concepts of correct weighting develop, they will be making deeper dives where the consequences of sudden ascent continue to mount and become progressively more severe. As the student begins to submerge and the lungs become more pressurized the manual operation mode of the valve is necessary for the diver to safely regulate the total amount of lift attached to their body underwater and thereby mitigate one of the major risks of diving.
As the buoyancy compensator is reduced to a device dedicated to contain the small amounts of lift actually required while underwater, some instructors are concerned that the diver will not be able to rely on the buoyancy compensator for a buoyant ascent. The problem with buoyant ascents is that they are very difficult to control when all the divers"" faculties are intact. In an emergency the ability to regulate a high lift buoyancy compensator at depth is very unlikely. Optionally, one of the forward chambers can be a low volume chamber designed for emergency ascent which has incorporated a rupture plug, disc or weld so that if the product is deployed unintentionally by use of a CO2 cylinder or the divers air cylinder, or accidentally, it will self destruct at a preset pressure differential, limiting its buoyant assist to the first leg of an emergency ascent allowing the diver a second chance to regain control and reduce their velocity to a safe rate. Some of the larger high lift surface flotation chambers may never fill to rupture so its containment system that regulates its inflation must be very secure to be assured that it will only be deployed intentionally, otherwise the diver would be in the same high lift rapid ascent predicament that they currently find themselves in with today""s product.
Incorporated within the multi-chambered heads up safety vest is a multi-function rescue safety product which can culminate into a raft for removal of the victim from the water and thereby confer protection from hypothermia. The needs and use of this rescue safety product determines its requirements for durability which in turn determines the type of fabric, its storable volume and therefore the location of the rescue product within the safety vest. The primary flotation device or life vest stays secured to the individual to assist them during their entry, and support them while they are deploying the rescue product. Once inflated if the product is not needed for rescue or signaling, the rescue product evolves into a raft that the individual can crawl into. The life vest remains on the victim protecting the individual should they be washed overboard as well as insulating the trunk, further helping to maintain core temperature.
The need and uses of a rescue device varies with the application. For the civilian airline passenger suddenly thrust into a survival situation, they are provided with a floating cushion or a lightweight inflatable life vest. In this situation a single use, ultra lightweight product is ideal. Such a rescue product might be constructed from an all welded mylar film. A multiplicity of layers would confer separate air chambers within the product providing for insulation, conferring a puncture protection while remaining small enough to fit inside a seat cushion or within a pocket of a purely inflatable life vest. To facilitate the single use products operation the oral inflator would lead to a manifold which could be constructed of differing diameters and/or which would pass through separate one way check valves of differing relief pressures. The diameter and/or pressure relief valves would direct the flow of air such that the chambers could be inflated sequentially. As pressure in the system builds up after inflating the first air chamber the second begins to inflate. The arrangement would allow for the inflation of a life ring first, followed by the rescue float, then if necessary a large outer tube would convert the rescue product into a raft with a canopy arch. The mylar, in addition to reflecting the radiant energy back towards the victim, is mirrored so that it is highly visible and radar reflective both of which would facilitate search and rescue. It structurally would resemble a single use raincoat. With the advantages conferred by this invention the victim could be of assistance to themselves and to others. Survival would be increased from minutes to days, dehydration would become the next serious threat to the survivor. An off the shelf plastic solar still could be easily included for trans-oceanic passages.
The water enthusiast on the other hand may find themselves in the water more often than the civilian airline passenger and their needs may tolerate slightly more bulk from the stored rescue product in exchange for reusability. The bulk increases because of the demands of a more durable and reusable product requires a more substantial choice of fabric. As the bulk increases, the location for stowing the rescue product becomes more critical. The ideal location is built into the back of the life vest where it is out of the way but securely and accessibly stowed until needed. In this posterior and inferior position the actions of the new and improved life vest are retained, that is the perimeter of the torso is supported by the rear inflation chamber of the life vest, stabilizing the victim against inadvertent rotation to a face down position. The location of the raft, is ideally within the walls of the life vest, protecting the raft from the shearing forces of entry, freeing the hands to assist entry and recovery once in the water. An envelope for containing the rescue product could be provided so that it could be attached to the inside or outside of any current life vest and thereby confer the protective advantages to all owners of a life vest without having to incur the cost of buying a new life vest. This would allow all current owners of a safety vest to upgrade to a dual chambered separating water survival system. This attachment system employs a hook and loop fastener looped through the arm holes and is universally adaptable to all life vests, of all sizes. Any releasable fastener such as buttons, zippers, snaps, hook and loop, etc. would allow for the rescue product and its stowage and release system to be located comfortably centered both up and down as well as side to side. While it could be positioned outside the life vest, its inclusion within the life vest will ensure its secure attachment. The inflation of the rescue product is determined by its use, cost, and available stowage space but since oral inflation is not restricted by shelf life, it is always present and most affordable. Inflation via a manifold will allow the rescuer to provide a rapidly inflated life ring to help stabilize the victim through the initial insult and then provide a float while the remainder of the chambers are inflated. In the current embodiment the rescue product is built into the safety vest or floating cushion, if anyone in the water intentionally or accidentally and is sequentially inflated through a series of rescue products that culminates in a raft for removal of the individual from the hypothermic effect of the water.
An additional advantage of the disclosed invention is directed to the adaptation necessary when the safety vest is used underwater by the scuba diver. In this application the heads up safety vest would be called a buoyancy compensator or BC. Because of the serious consequences of rapid ascent on pressurized lungs, in addition to the reliable regulation of the high lift surface flotation component of the buoyancy compensator, the primary buoyancy compensation bladder should be variable size. By design the buoyancy compensator is to be used underwater where it is vulnerable to inflation from entrapped pressurized air at two to three atmospheres, as well as subject to inflation from panicked misuse or mechanical failure of the power inflator, all causes leading to the same result, dangerously rapid ascent rates. The volume of the bladder should be tailored to the dive environment. The dedicated buoyancy compensator can be adjusted to the lowest volume needed to accomplish the goal of compensating for compression of thermal protective gear and the resultant loss of buoyancy. As the dive environment changes, so does the need for thermal protective gear. In tropical water minimal or no protective gear is worn and therefore the diver has nothing to compress and so experiences no loss of buoyancy at depth. For the diver in a bathing suit, the need for a power inflatable bladder underwater is limited to the shift in buoyancy that occurs in their air cylinders, and usually is well under 5 or 6 pounds of lift. This chamber is only needed to cover the initial overweighting needed to allow the diver to be neutral at the end of the dive in order to make a safety stop. This product should not be called a buoyancy compensator as a first step in reeducating the diving population about the dangers of power inflatables underwater.
In cold water, at 120 feet of depth, a 190 lb. diver in a xc2xc inch neoprene wet suit experiences a loss of 9 lbs. of lift due to compression of the wet suit. Most sport divers are smaller and therefore are wearing less neoprene, dive in warmer waters and/or making shallower dives. There is no justification for subjecting a diver to unnecessary risks of rapid ascent. Due to the extreme danger of pulmonary rupture and secondary air embolism that results from a rapid uncontrolled ascent it is imperative that the buoyancy compensation chamber be restricted to the lowest volume absolutely necessary to accomplish its goal. Any lift over and above the minimum amount exposes the diver to unnecessary risk. The diver doing repetitive dives in one day is advised to do their deepest dive of the day first and will need a buoyancy compensation capacity commensurate with their thermal protective gear and dive plan. As the dives become shallower and consequently warmer as well, the volume of an adjustable buoyancy compensator can be reduced, and consequently reduce the divers exposure to the risk of rapid ascent. Recommended ascent rates are dropping from 60 feet per minute to 20-30 feet per minute. The medical literature notes that a 30 lb. buoyancy compensator can produce average velocities in excess of 250 feet per minute from less than ten feet under the water. For several generations, divers dove without a buoyancy compensator so its use cannot be construed as critical. The advent of this convenience product has resulted in ballistic ascent rates because of the air entrapped inside the product which is pressurized at depth which then doubles and possibly quadruples upon ascent depending on the initial depth. An inexperienced diver in an xe2x80x9cout-of-airxe2x80x9d situation is prone to forget about the intellectual concept of arterial gas embolism in the hypoxic and hypercapnic driven race to the surface, only to die from an arterial gas embolism before ever getting a chance to drown. Drowning is a slow, reversible process that lends itself to rescue for quite some time after the event, unlike arterial gas embolism. When using an adjustable dedicated buoyancy compensator the diver can very precisely control their exposure to the dangers of an emergency ascent through the water column and thereby significantly reduce the risks of rupturing a lung and suffering an arterial gas embolism to the brain or heart or similarly reduce the risks of suffering the bends because of missed decompression stops.
An alternate location for a separating forward surface flotation chamber is for its inclusion within the shoulder straps. The redundant personal flotation device is designed to be separated away from the remainder of the dive gear to provide complete duplication of personal flotation devices in the event of failure of the primary chamber. The chamber can also be used as a rescue, signaling, salvage product or snorkeling vest.
Appropriately sized releasable shoulder trim weights offset the operation of the buoyancy compensator underwater, improving swimming position, decreasing frontal area, producing less hydrodynamic resistance and consequently less diver fatigue. Once again, the shoulder trim weight results in a reduction of the consolidated weight belt with its inherent advantage of protecting the diver from accidental loss of all ballast at one time.
In summary, a multiple chambered life vest can be of a low volume, low lift, and low profile design as long as at least two points in need of buoyancy are covered, behind the neck and at the umbilicus and one point of ballast along the vertical posterior axis. Excessive buoyancy can be extremely detrimental either because the product is not actually worn because it is too bulky or because side righting moments have been created that jeopardize the airway. The separating chamber in the hands of a conscious, capable user can be removed providing a signaling device for facilitating search and rescue efforts or used as a rescue board minimizing the risk associated with attempting to rescue another victim who has become hypoxic. After the initial insult has been survived the user can deploy the incorporated inflatable rescue product that sequentially inflates into a life ring, then rescue board and distress marker and culminates in a raft to remove the victim from the water with its inevitable and often rapid hypothermia. The entire water safety survival system constructed for a single use application could easily fit within the air line seat cushion, dramatically improving survival statistics for accidents at sea.
The multi-chambered heads up safety vest as adapted for the scuba diver allows for reliable segregation of a variety of high lift surface flotation chambers while underwater. In addition a variable volume dedicated buoyancy compensator allows the diver to further reduce the amount of lift attached to the smallest amount necessary for a particular dive environment. The combination of these two improvements will markedly reduce the largest cause of pulmonary barotrauma, and secondary embolism, a major cause of injury and death in the field of diving.
The inclusion of a couple of pounds of weight integrated into the posterior axis of the victim""s vest will allow the victim to overcome numerous minor righting moments that can place the airway of the exhausted or distressed victim under the water leading to drowning another major cause of death in the sport of diving. The benefits of the tank compensating keel weight are so dramatic that they can be included into a separate product that can retrofit existing buoyancy compensators, converting them into a heads up product. The inclusion of the multi-function rescue product within the walls of the buoyancy compensator confers on that diver the ability to respond to a number of problems frequently encountered by the diver in rescue, marking and salvage.
Thus, a water safety and survival system that provides a multi-chambered personal flotation device that operates on minimal volume to create a single heads-up righting moment that reliably stabilizes an unconscious victim with his airway out of the water is disclosed in one embodiment. This is accomplished with a minimal amount of lift, less deflated bulk, improved cosmetic appeal, and reduced cost. These combined advances result in a safety vest conducive to actually being worn, a key feature for a safety vest. The system also provides for incorporation of a separating second inflatable life ring, rescue board, artificial respiration assist platform, and ultimately a raft for removal of the victim from the water to protect him from hypothermia. This sequentially inflated, multi-chambered, multi-faceted inflatable rescue product is incorporated within the body of the safety vest. The incorporation of a wide range of rescue products into the body of the person flotation device will reduce the incidence of that dual tragedy that occurs when the rescuer becomes the second victim. This water survival system, when adapted to the special needs of the scuba diver, requires the incorporation of a tank compensating counterweight to offset the deleterious effects of a buoyant empty tank whose buoyancy can force the diver""s airway under the water. Further adaptation for use underwater also includes a system to adjust the volume of the primary buoyancy compensation chamber and variable valve for segregation and reliable regulation of one or more additional surface flotation chambers underwater. The design of the separating chambers coincides with responsibilities and goals of the diver. These and more modifications for the safe underwater use of the heads-up safety vest are critical in order to mitigate the risk of rapid ascent and its consequences, arterial gas embolism and decompression sickness.
In accordance with these and other objects which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings.